What is what does it mean when a judge says sustained?

When a judge says "sustained" during a trial, it means the judge agrees with an objection that was raised by one of the attorneys. The attorney who made the objection was successful in convincing the judge that a particular question, piece of evidence, or line of questioning was improper under the rules of evidence.

The effect of an objection being sustained is that the question cannot be answered, the evidence is not admitted, or the line of questioning must stop. It prevents potentially inadmissible or prejudicial information from being presented to the jury.